DWI – Don’t Get Caught Below the Legal Limit

Lawyers in this firm have been seeing a large number of arrests for DWI in New York in which the blood alcohol content (BAC) as determined by the breath test is exactly at or even below the legal limit. Jurisdictions that seem to be prosecuting cases that are either exactly on or a little below the legal limit have included Brooklyn and various jurisdictions in Westchester County including the Village of Larchmont, the Town of Greenburgh and the Village of Mamaroneck. While I have not seen any statistics on this phenomenon we have handled many of these cases and have heard about others.

The problems with prosecuting these cases are significant and in order to fully understand the issue one must have at least a basic knowledge of how breath tests work. Firstly, it’s important to understand that the statutory blood alcohol levels refer to the level of alcohol in a person’s blood. Despite this, in the overwhelming majority of cases it is a person’s breath that is tested not their blood. In order the convert the percentage of alcohol in breath into the blood alcohol content defined by statute, the breath machine must make a calculation based upon something called the “blood-breath” relationship. Since the “blood breath” relationship is not the same for every person, this builds in a certain level of error in determining blood alcohol content.
If a person registers a .08 blood alcohol content, even a slight error in the calculation can mean the person is really slightly below the legal limit and therefore not guilty of diving with a blood alcohol content above the legal limit. This fact would not preclude a conviction for something called common law intoxication in which a person’s intoxication can be proven through other factors such as swerving, or failing coordination tests (often called field sobriety tests).

The other issue is that we have seen arrests for blood alcohol levels as low as .068 and heard about arrests for blood alcohol contents in the .05’s. This means that you can be arrested for consuming as few as 2 drinks in two hours depending on your weight, sex and level of experience. This site put together by the State of Connecticut contains several charts that show the relationship between number of drinks and blood alcohol levels.

The bottom line is be careful. It now seems abundantly clear that in certain jurisdictions if you are stopped and have the odor of alcohol on your breath you may be arrested even if your blood-alcohol content is below the legal limit.